Transmission of Internet signals and of digital television (TV) signals poses different but continuing challenges for each activity. Internet signal transmission faces the problems of reliable broadcasting and multicasting of messages, provision of mobility for signal transmitter and for recipient, and limitations on information transfer rate (“speed”). Transmission of digital TV signals faces the problems of providing an interactive system, providing point-to-point information transfer capacity, and mobility of the recipient. The system should be efficient in the sense that the payload or data portion of each transmitted frame is a large fraction of the total frame. At the same time, the system should be able to identify, and compensate for, varying characteristics of the transmission channel, including but not limited to time delay associated with transmission of each frame.
What is needed is a system that provides timing recovery, carrier recovery and estimation of channel characteristics associated with signal propagation in a channel, and that also serves as a guard interval and as a frame synchronizer for the transmitted signal.